In multiactive photoconductor elements of the type employing a charge generating layer and a charge transport layer, it has been common to employ in the charge transport layer either a polymer, such as polyvinyl carbazole, or a composition comprised of an electron-donating, low molecular weight organic compound dissolved in an insulating binder polymer. Such charge transport layers commonly suffer from problems upon repeated use, such as high dark decay, fluctuations in surface potential, insufficient electron charge transport activity, a gradually increasing residual potential or the like. Consequently, the art of photoconductor elements continues to seek new charge transport agents which exhibit sufficient sensitivity, but which do not exhibit disadvantages such as above indicated which might restrict their utilization in positively charged photoconductor elements.
Certain charge transport agents, such as trinitrofluorenone (TNF), which do exhibit a useful level of sensitivity, suffer from the further disadvantage that they are now suspected to be carcinogens.
Although cyclic bis-dicarboximide compounds have previously been proposed for use as sensitizers for photoconductor materials (see U.S. Pat. No. 4,442,193), so far as now known, no one has heretofore proposed the use of cyclic bis-dicarboximides as charge transport agents in photoconductor elements.